My preview's doesn't always seem to work in CS6. It will live update if I move a camera etc, but thinks like depth of field I cannot get working. I simply cannot see any depth of field with the aperture turned right up, draft 3D on with 3D layers space apart on the z axis.
I know it's probably some ridiculous button in cs6 I cannot find but any help would be appreciated.
Google searches for this seem to only show people who haven't got 3d layers, live update or draft 3d ticked.
Depth of Field effects do not show up in Draft 3D, only if you've got the Fast Previews set to 'Off (Final Quality)' or 'Adaptive Resolution'. Draft 3D is just that - a quick & nasty version without stuff like anti-aliasing, shadows, reflections or depth of field.
Note that is you're using the 'Classic 3D' renderer, you'll have to use mush larger values for the Aperture and Blur Level camera settings than if you're using 'Raytraced 3D'.
Crank the camera settings to some crazy values like a 400-pixel aperture and a blur level of 800% to check if your depth of field is working, then refine it to a more sensible level. Don't forget the invaluable select an object AND a camera, then right-click to select 'set focus to layer'.